Nation in Brief / WASHINGTON, D.C.

Replacements for DEET foreseen

Researchers have identified seven possibilities for the next generation of mosquito repellents, some of which may work several times longer than the current standard-bearer, DEET. Tests will begin this summer to make sure the prospective repellents are safe to use directly on the skin.

The new repellents aren't likely to be available commercially for a few years. Early tests have been promising, with some chemicals repelling mosquitoes for as long as 73 days and many working for 40 to 50 days, compared with an average of 17.5 days with DEET, according to a study in today's edition of Proceedings of the National Academy of Sciences.

Biting insects such as mosquitoes and ticks can spread diseases such as encephalitis, Lyme disease, Rocky Mountain spotted fever and malaria.